Re: Opinions on removing /proc/tty?

["Antonino A. Daplas" <adaplas@gmail.com>]

Randy.Dunlap wrote:
> On Sun, 9 Jul 2006 09:45:06 -0400 Jon Smirl wrote:
> 
>> On 7/9/06, Antonino A. Daplas <adaplas@gmail.com> wrote:
>>> Jon Smirl wrote:
>>>> On 7/9/06, Randy.Dunlap <rdunlap@xenotime.net> wrote:
>>>>> On Sat, 8 Jul 2006 01:56:02 -0400 Jon Smirl wrote:
>>>>>
>>>>>> On 7/8/06, Randy.Dunlap <rdunlap@xenotime.net> wrote:
>>>>>>> I don't know how well this is an answer to your question,
>>>>>>> but I would like to be able to find a list of registered "consoles,"
>>>>>>> whether they be serial, usbserial, netconsole, lp, or whatever.
>>>>>>> /proc/tty/drivers does that partially.
>>>>>> Console is an overloaded word. Do you want to know where it is legal
>>>>>> to send system log output to, or do you want to know where you can log
>>>>>> in from? There was a thread earlier that talked a little about
>>>>>> controlling this.
>>>>> I have a working definition:
>>>>> I want to see a list of drivers that have called register_console().
>>>>>
>>>>>>> I have a patch that also does it in /proc/consoles:
>>>>>>>   http://www.xenotime.net/linux/patches/consoles-list.patch
>>>>>>> Is somewhere in /sys the right place to find a list of all consoles?
>>>>>> /sys is the right place for this info but a class does not exist for
>>>>> it yet.
>>>>>
>>>>> I want a list of registered consoles.  How would I express that in /sys ?
>>>> You could make the list appear as an attribute in
>>>> /sys/class/tty/console. You will need to all a little sysfs code after
>>>> the console tty device is created.
>>>>
>>> That would violate the one file, one value rule and GregKH will drop
>>> it like a hot potato.
>>>
>>> A better solution is to have /sys/class/console.
>> The one value rule is for things that can be changed.

No, it also applies to read-only attributes.

> For, example, I
>> see no problem with using the graphics/modes attribute to see a list
>> of legal modes, and then using graphics/mode to set or view the
>> currently active mode.

Yes, a lot of the fbdev attributes violate this rule. There's some
discussion in fbdev-devel list on how to overhaul this.
 
 Why can't we have a read-only attribute that
>> displays the list of available consoles?
> 
> We should be able to do that somewhere/somehow, but /sys does
> not allow for it in one file, like Tony said.

We can do it in debugfs, or do it like this in sysfs

/sys/class/console--- con0
                  :
                  --- con1
                  :
                  --- con2

Tony